Waterproofing a Shower

I received this question from a reader recently and would like to take the time to answer it.

QUESTION

“How can I ensure that water won’t penetrate through my tiled shower into the walls?” -Jack, CA

ANSWER:

The most important things you can do to protect the walls under your tile in the shower are the items you put between the wall and tile. You also want to seal up all cracks, corners, edges, etc. And a little maintenance goes a long way in protecting your shower as well. Follow the steps below to help prevent water exposure in your walls. (This post however will not help protect you from leaks in your plumbing fixtures- that’s a whole other problem)

1. Make sure you have a shower pan installed. Shower pans can come in a pre-made form or in a liner form (in which you lay by hand). The shower pan is made for shower floors and needs to come up the walls at least 6-8 inches. Be sure that the shower pan is installed before the cement backer board on the walls is installed. In other words, the backer board will overlap the top of the shower pan. Shower pans are a VITAL part of waterproofing your shower floor/walls.

2. Make sure all shower walls are hung with cement backer board or floated with concrete. This is what you will actually tile onto. To add even more protection, they make a plastic sheeting/water proof membrane you can attach to the backer board as well (Schluter Systems makes a great product). So, it would be the frame of the wall, the backer board, the waterproof membrane and then the tile.

3. Make sure ALL corners and edges in the shower are sealed with grout caulk.

4. Seal ALL grout joints with a grout sealer. (Read our post here on how to seal grout) If you have a porous tile, like slate or travertine, then seal the tile as well.

5. Silicone around all fixtures in the shower.

6. Maintenance, maintenance, maintenance! Once a year, re-caulk/silicone corners, edges, cracks, and fixtures. You can tear out old caulk first by using a caulk remover like “Caulk-Be-Gone”,to soften the existing caulk. Then take a plastic putty knife, or something similar, and remove the existing caulk. You can also use paint thinner to clean up any remaining adhesive or gunk. (Be sure to wear eye protection, gloves and ventilate the area) Before replacing with new caulk, spray the areas with a bleach cleaner to ensure all mildew or mold is killed. Let it dry before reapplying caulk. You can also see our video here to learn how to caulk corners. Be sure to wait 24 hours before showering so that it can dry completely (unless you use a quick dry caulk). This is also a great time to reseal grout and possibly tile. You may also want to check to make sure there is putty around escutcheons inside of faucets in shower (the plumber should have installed this). This would require removing fixtures so only do this if you suspect water gathering around the inside of fixtures.